Bacterial Infections and Importance of Bacteria

Bacterial Diseases Tuberculosis Bubonic plague Tetanus Leprosy Lyme disease Bacterial meningitis E. coli Typhoid fever Rheumatic fever Diphtheria Scarlet fever Cholera MRSA

What is MRSA? MRSA = Methicillin-resistant Staphylococcus aureus Commonly found on skin Resistant to antibiotics usually used for staph infections…but usually treatable Can cause acne, boils, toxic shock syndrome, bone infections, pneumonia Passed thru skin-to-skin contact or through shared items/surfaces contacted

Ring-around-the-Rosies A song about the “Black Death” “Ring around the rosies” refers to the rosy cheeks “Pocket full of Posies” refers to the people carrying flowers in the pocket to cover up the stench “Ashes, ashes we all fall down” refers to the ashes from the dead and the # of dead

Why do we get sick from bacteria? Bacteria produce 2 kinds of toxins: 1. Endotoxin – found within the cell walls of the bacteria All produce the same general symptoms: fever, weakness, intestinal problems Can produce more serious problems with circulatory system (ex. Typhoid fever, Rheumatic fever)

2. Exotoxin – a waste product of the bacteria’s function Are more deadly/potent Most can live without oxygen (Ex. Botulism) Botox uses a small amount of the botulism toxin to temporarily paralyze muscles

Examples of bacteria Typhoid Fever Botulism

Bacterial Cell Wall Made of combination of sugar and protein One way to classify bacteria is stain them by a process called Gram staining: – Gram-positive bacteria - bacteria stains purple because the cell wall is mostly sugar (easier to kill) – Gram-negative bacteria - bacteria stain pink because the wall is mostly made of protein (harder to kill)

Gram-positive vs. Gram-negative

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Controlling Bacteria Most bacteria are controlled by nature (controlled by food or other resources) Dehydration – removing water Temperature control – making it too hot or too cold to live – Pasteurization: the process of heating food (ex. Milk) to kill bacteria – Refrigeration – slows down the reproduction of bacteria

Antibiotics: a substance produced by a microorganism which can kill/inhibit the growth of a different microorganism – Penicillin works by interfering with the ability to make the cell wall (dissolves the sugar) – Tetracyline interferes with protein synthesis (broad spectrum antibiotic) – Erythromycin interferes with protein synthesis

Alexander Flemming English scientist who discovered penicillin (on accident) in 1928 Penicillin is a toxin (poison) produced by penicillium fungus Was a major medical advance used in WWII

*Notice the clear ring around the disk in the middle… no bacteria!

Bacteria resistant to antibiotics GonorrheaSyphilis

Economic Importance Nitrogen-fixation – bacteria that can change nitrogen in the air to a usable compound for us – Ex. crop rotation Recycle nutrients, decomposers Food – Creates flavors/smells in cheese, yogurt, vinegar

In the medical field – We use bacteria to “grow” vaccines – Some bacteria kill other strains of bacteria (ex. On skin…staphylococcus epidermis) – Estimated that ½ of all disease is caused by bacteria Produces jobs Produces $$ for prescription drug companies

Question Based on the colors of these bacteria, what testing method was used? – Gram Staining Are they gram-positive or gram-negative? – Both…they’re gram- variable